This invention relates to a fuel injection valve assembly for internal combustion engines, and more specifically to such a valve assembly well adapted for use with a jerk pump for injection of fuel oil into a diesel engine.
The combination of jerk pump and injection valve assembly represents an example of fuel injection systems heretofore suggested and used for the delivery of fuel into internal combustion engines notably including diesel engines. Receiving successive metered charges of fuel from the jerk pump, the injection valve assembly must introduce the fuel into the engine combustion chamber against the highly compressed air at the end of the compression stroke, as required for combustion in the diesel cycle. Considerable pressure is also required to break up the fuel into the fine-spray pattern desired for good combustion.
A problem common to such conventional fuel injection systems arises from the fact that the fuel pumps are driven by the engine. Thus, upon decrease in engine speed, pump output and injection pressures decrease correspondingly, adversely affecting combustion and engine performance.